Merocyanines and a process for the preparation thereof



: UNITEDLSTATES PATENT OFFICE MEROCYANINES AND A PROCESS FOR THE PREPARATION THEREOF Leslie G. S. Brooker and Russel H. Van Dyke,

Rochester, N. Y., assignors, by mesne assignments, to Eastman Kodak Company, Jersey City, N. .L, a corporation of New Jersey No Drawing. Application July 5, 1935, Serial No. 29,917

9 Claims.

This invention relates to dyes of a new class related in certain respects to dyes of the cyanine classWIt has recently been proposed to call the dyes-oi this newclass merocyanine dyes. A num- ;'ber:of dyes of the merocyanine class have been described by Leslie G; S. Brooker in his copending application Serial No. 739,502, filed August 11,

1934.. In the above-referred to copending application of Leslie G. S. Brooker, dyes of the following general formula are described:

, wherein A represents oxygen or sulfur, R, represents an 'alkyl group and Y and Z represent the non-metallic atoms necessary to complete a fivemem beredxor six-membered heterocyclic nucleus. Specifically described are dyes wherein A represents oxygen, Z represents the non-metallic atoms necessary towcomplete a five-membered rhodanine nucleus 1011 a six-membered 2,4,6-triketohexahydropyrimidine nucleus and Y represents the nonmetallic atoms necessary to complete a six-membered' pyridine, quinoline or naphthoquinoline' nucleus. Such dyes were prepared by condensing a quaternary salt of a 2-halogeno-pyridine, a 2- halogeno-quinoline or a 2-halogeno-naphthoquinoline with a rhodanine or aZgLG-triketohexahydropyrimidine, in the presence of an acid binding agent.

A Now we have found that dyes of the above for mula can be prepared by condensing a quaternary salt o'fa 2''substituted mercapto-pyridine or quinoline with a heterocyclic compound,containing a nuclear methylene group adjacent to a' nuclear carbonyl'or thiocarbonyl group. We'have further found that new dyes of the above formula can be prepared by employing a quaternary salt of a l substituted mercaptobenzothiazoleor benzoxazole. Allof the dyes which can be prepared bygournew process areuseful for improving and extending the normal sensitivity of photographic gelatinoesilver-halide emulsions.

; -.The object of our invention, therefore, is to providenew, meroecyanine dyes. A further object is to provide a process for the preparation of mero-cyanine dyes.

ll. become apparent upon a complete perusal h sn i eai nt Other more specific objects.

Our new process can be illustrated by the following specific reactions:

0 ll 0 CH N \j l I H; C011 SC s=0 5 s CzHs \I 3-phenylrhodanine ethiodide of 2-phenylthioquinollne o I! ceasmm 02135 5-(l-ethyl-2-quinolylidene)-3-phenylrho(lanine and 0 ll C S 00H -N I on, corns- 02115 1 3-phenylrhodanine ethiodide of l-phenylthiobenzothiazole O 2'. S CaHt-N 9:0 Oo aSH+HI densations, the strong organic bases, such as triethylamine, are preferable. The condensations take place without the application of heat, but only quite slowly. The 2-substituted-mercaptopyridines and quinolines used herein are described in the .copending application of Leslie G. S. Brooker and Grafton H. Keyes, Serial No. 739,127, filed August 9, 1934 (now United States Patent 2,117,936, dated May 17, 1938). The l-alkylthiobenzothiazoles and l-alkylthiobenzoxazoles: can be prepared in known manner, e. g. as described in British Patent 424,559.

The following examples serve to illustrate our invention, but are not intended to be limiting except as is indicated in the appended claims.

EXAMPLE 1.-5- (1-ethyl-2-quinolylidene) rhodanine 0.44 g. (1 mol.) of rhodanine, 1.3 g. (1 mol.) of Z-phenylthioquinoline ethiodide and 0.36 g. (1.05 mol.) of triethylamine were refluxed in 15 cc. of absolute ethyl alcohol for fifteen minutes. The dye separated from the chilled solution. Yield 69%. Following recrystallization from glacial acetic acid, the dye was obtained in the form of red crystals with a green reflex. Yield 52%. 2-(n-butylthio)-, 2-(p-to1ylthio)-, 2(fl-naphthylthio)- or 2-(l-benzothiazolylthioquinoline can also be condensed with rhodanine to yield the same mero-cyanine.

EXAMPLE 2.3-ethyZ-5- (1 -ethyl-2-quinolylidene) rhodanine 0.32 g. (1 mol.) of B-ethylrhodanine, 0.8 g. (1 mol.) of 2-phenylthioquinoline ethiodide and 0.21

g. (1.05 mol.) of triethylamine were refluxed in 15 cc. of absolute ethyl alcohol for fifteen minutes. The dye separated from the chilled solution. Yield 69%. Following recrystallization from glacial acetic acid, the dye was obtained as red crystals. Yield 50%.

EXAM LE 3.5 (1 -ethyZ-2-quinolylidene) -3-phenl-rhodanine EXAMPLE 4.-3-ethyZ-5- (1 -ethyl-2-quinolylidene) -1-phenyZ-2-thiohydcmtoin 1.1 g. (1 mol.) of 3-ethyl-1-phenyl-2-thiohydantoin, 2.0 g. (1 mol.) of Z-phenylthioquinoline ethiodide and 0.53 g. (1.05 mol.) of triethylarnine were refluxed for fifteen minutes in 20 cc. of absolute ethyl alcohol. The dye separated from the chilled solution. Yield 73%. Following recrystallization from methyl alcohol (365 cc. per gram of dye), the dye was obtained as dark greenish crystals. 1

The 3-ethyl-1-phenyl-2-thiohydantoin used in this preparation was prepared by heating 17.0 g. (1 mol.) of phenyl glycine ethyl ester and 8.7 g. (1 mol.) of ethyl isothiocyanate in an open flask on the steam bath for 48 hours. The heavy viscous syrup so obtain-ed was diluted with methyl alcohol, precipitating the compound. Yield 63%.

Following recrystallization from methyl alcohol (10 cc. per gram of compound), the compound was obtainedin a yield of 50%.

EXAMPLE 5.--3-ethyZ-5- (I-ethyl-Z-quinolylidme) Z-thio-Z, 4 (3, 5) -0arazoledione 0.7 g. (1 mol.) of 3-ethyl-2-thio-2, 4 (3, 5)- oxazoledione, 2.0 g. (1 mol.) of Z-phenylthioquinoline ethiodide and 0.53 g. (1.05 mol.) of triethylamine were refluxed in 20 cc. of absolute ethyl alcohol for fifteen minutes. The dye separated from the chilled solution. Yield 63%. Following recrystallization from methyl alcohol (300 cc. per gram of dye), the dye was obtained as orange prisms. Yield 53%.

EXAMPLE 6.5 (Z-ethyZ-I -benzothiazylidene) rhodanine 1.1 g. (1 mol.) of l-methylthiobenzothiazole ethiodide 0.44 g. (1 mol.) of rhodanine and 0.35 g. (1.05 mol.) of triethylamine were refluxed in 20 cc. of absolute ethyl alcohol for fifteen minutes. The dye separated from the chilled solution. Yield 75%. Following recrystallization from pyridine (30 cc. per gram of dye), the dye was obtained as a bright yellow powder. Yield The 1methylthiobenzothiazole ethiodide used in this preparation was made by heating l-methylthiobenzothiazole (20 g. 1 mol.) and ethyl iodide (21.7 g.; 1.25 mol.) for 48 hours on the steam bath. The yield was 31%.

The 1-methylthiobenzothiazole used above was prepared by treating l-mercaptobenzothiazole g.; 1 mol.) with dimethyl sulfate (57 g.; 1.5 mol.) in the presence of aqueous sodium hydroxide (57 g. 1.5 mol.). Yield 92%, Following distillation the l-methylthiobenzothiazole was obtained as a clear liquid. Yield 80% l-rnethylthiobenzoxazole and its ethiodide, as well as l-phenylthiobenzoxazole, l-phenylthiobenzoxazole, l-(n-butylthio) -benzothiazole and l-(n-butylthio) -benzoxazole, and their ethiodides can be made in the same manner. These ethiodides can all be condensed with rhodanines, hydantoins, 2,4 (3,5)-oxazolediones and the like. See Example 13.

EXAMPLE 7 .3- thyZ-5 (2-ethyl-1 -benzothiozylidene) -rh0danine 0.53 g. (1 mol.) of 3-ethylrhodanine, 1.1 g. (1 mol.) of l-methylthiobenzothiazole ethiodide and 0.35 g. (1.05 mol.) of triethylamine were refluxed in 15 cc. of absolute ethyl alcohol for fifteen minutes. The dye separated from the chilled solution. Yield 93%. Following recrystallization from pyridine (25 cc. per gram of dye), the dye was obtained as yellow crystals with a blue reflex. Yield 75%.

8.5- (Z-ethyl-i -benzothi zylidene) -3- phenyZ-rhodanine EXAMPLE 0.7 g. (1 mol.) of 3-phenylrhodanine, 1.1 g. (1 mol.) of l-methylthiobenzothiazole ethiodide and 0.35 g. (1.05) mol.) of triethylamine were refluxed in 15 cc. of ethyl alcohol for fifteen minutes. The dye separated from the chilled solution. Yield 90%. Following recrystallization from pyridine (90 cc. per gram of dye), the dye was obtained as bright yellow crystals. Yield 73%.

EXAMPLE 9.-3-ethyZ-5 (2 -ethyl-1 -benzothiazylidene) -2-thio-2,4 (3,5) -o.'caeoledione EXAMPLE 10.5- (Z-ethyl-l -benzothiazylidene) 1,3-diphenyl-2-thiohydantoin 0.9 g. (1 mol.) of 1,3-diphenyl-2-thiohydantoin, 1.1 g. (1 mol.) of l-methylthiobenzothiazole ethiodide and 0.35 g. (1.05 mol.) of triethylamine were refluxed in 15 cc. of absolute ethyl alcohol for fifteen minutes. The dye separated from the chilled solution. Yield 77%,. Following recrystallization from glacial acetic acid (35 cc. per gram of dye), the dye was obtained as dull yellow crystals. Yield 40%.

EXAMPLE 1 1.1 (2-6thyl-1 -bengothiazylidene) 2 (1 -thionaphthenone EXAMPLE 12.-5- (2-ethyZ-1benzoihiazylidene) -2 cliphenylamino-4 (5) t hiazolone 0.45 g. (1 mol.) of 2-diphenylamino-4(5) -thiazolone, 0.56 g. (1 mol.) of l-methylthiabenzothiazole ethiodide and 0.18 g. (1.05 mol.) of absolute ethyl alcohol were refluxed in absolute ethyl alcohol (15cc) for fifteen minutes. The dye separated from the chilled solution. The yield of crude dye was Following recrystallization from glacial acetic acid (50 cc. per gram of dye), the dye was obtained as a pale yellow powder. Yield 23%.

EXAMPLE 13.-3-ethyZ-5- (Z-ethyZ-I -benzomazylidene) -rhodam'ne 1.61 g. (1 mol.) of 3-ethylrhodanine, 3.22 (1 mol.) of l-methylthiobenzoxazole ethiodide and 1.06 g. (1.05 mol.) of triethylamine were refluxed for fifteen minutes in cc. of absolute ethyl alcohol. The dye separated from the chilled solution. Yield 50%. The dye was recrystallized from glacial acetic acid and obtained as yellow crystals. Yield 35%.

The l-methylthiobenzoxazole ethiodide used in this preparation was made according to. the process given in Example 6 for l-methylthiobenzothiazole ethiodide.

EXAMPLE l4.--zx- (Z-ethyl 1 beneothiazylzdene) benzo'ylacetonitrile substituted mercapto-pyridine orquinoline or a quaternary salt of a l-substituted mercaptobenzothiazole or benzoxazole with a heterocyclic compound containing a nuclear methylene group adjacent to-a nuclear carbonyl or thiocarbonyl group. 7

What we claim as our invention and desire to be secured by Letters Patent of'the United States 1. A process for preparing a merocyanine dye comprising condensing, in the presence of a trialkylamine condensing agent having a dissociation constant of the order of that of triethylamine, a cyclammonium alkyl quaternary salt containing a reactive alkylthio group in the alpha position to the ammonium nitrogen atom, with a heterocyclic compound containing a nuclear reactive methylene group adjacent to a nuclear group selected from the group consisting of carbonyl and thiocarbonyl groups.

2. A process for preparing a merocyanine dye comprising condensing, in the presence of a trialkylamine condensing agent having a dissociation constant of the order of that of triethylamine, a cyclammonium alkyl quaternary salt containing a reactive alkylthio in the alpha position to the ammonium nitrogen atom, with a heterocyclic compound containing a nuclear reactive methylene group adjacent to a nuclear carbonyl group. H

3. A process for preparing a merocyanine dye comprising condensing, in the presence of triethylamine condensing agent, a cyclammonium alkyl quaternary salt containing a reactive alkylthio group in the alpha position to the ammonium nitrogen atom with a heterocyclic compound containing a nuclear reactive methylene group adjacent to a nuclear carbonyl group.

4. A process for preparing a merocyanine dye comprising condensing, in the presence of a trialkylamine condensing agent having a dissociation constant of the order of that of triethylamine, a Z-alkylthioquinoline alkyl quaternary salt with a heterocyclic compound containing a nuclear reactive methylene group adjacent to a nuclear carbonyl group.

5. A process for preparing a merocyanine dye comprising condensing, in the presence of triethylamine condensing agent, a 2-alkylthioquinoline alkyl quaternary salt with a heterocyclic compound containing a nuclear reactive methylene group adjacent to a nuclear carbonyl group.

6. A process for preparing a merocyanine dye comprising condensing, in the presence of a trialkylamine condensing agent having a dissociation constant of the order of that of triethylamine, a l-alkylthiobenzothiazole alkyl quaternary salt with a'heterocyclic compound containing a nuclear reactive methylene group adjacent to a nuclear carbonyl group.

'7. A process for preparing a merocyanine dye comprising condensing, in the presence of triethylamine condensing agent, a 1-alkylthiobenzothiazole alkyl quaternary salt with a heterocyclic compound containing a nuclear reactive methylene group adjacent to a. nuclear carbonyl group.

8. A process for preparing a merocyanine dye comprising condensing, in the presence of a trialkylamine condensing agent having a dissociation constant of the order of that of triethylamine, a l-alkylthiobenzoxazole alkyl quaternary salt with a heterocyclic compound containing a nuclear reactive methylene group adjacent to a nuclear carbonyl group.

9. A process for preparing a merocyanine dye comprising condensing, in the presence of triethylamine condensing agent, a l-alkylthiobenzoxazole alkyl quaternary salt with a heterocyclic compound containing a nuclear methylene group adjacent to a nuclear carbonyl group.

LESLIE G. S. BROOKER. RUSSEL H. VAN DYKE. 

